1. Field of the Invention
The invention relates generally to an exposure apparatus, and more particularly, to an exposure apparatus with favorable performance.
2. Description of Related Art
With the continuous advancement of the liquid crystal display (LCD) device towards to the large-size display standard, the market is gravitating towards LCDs having characteristics such as high contrast ratio, rapid response, and wide viewing angle. Therefore, the wide viewing angle techniques of the liquid crystal display panel are continuously developed in order to enhance the viewing angle of the large-size display device. At the current stage, LCD panels employing the multi-domain vertical alignment (MVA) technique are some of the most common, for example, the MVA LCD panel and the polymer stabilized alignment (PSA) LCD panel are popular.
Taking the PSA-LCD panel for example, the pixel electrodes in a PSA-LCD panel include a plurality of strip patterns, and slits are used to separate each set of strip patterns. The strip patterns can divide the pixel electrodes into four alignment regions (domains), for example, which are conducive to the liquid crystal molecules in the liquid crystal layer tilting in different directions, thereby meeting a wide viewing angle requirement. However, in view of current technologies, a line width of each strip pattern and a spacing (e.g., a width of the slits) between two neighboring strip patterns are typically 5 μm and 3 μm, respectively. When line width/spacing is 5 μm/3 μm, liquid crystal efficiency of the PSA-LCD panel is not good enough. Therefore, in order to further enhance the liquid crystal efficiency of the PSA-LCD panel, the widths of the strip patterns and the slits need to be reduced.
Typically, a pitch of the strip patterns is mainly determined by the patterned photoresist layer of the mask layer, and the pitch of the patterned photoresist layer is determined by the design of the width and the pattern of the shielding patterns of the mask. Moreover, since a lens group of an exposure apparatus is formed by a plurality of strip lenses arranged parallel to each other, an overlapping region is formed between any two neighboring strip lenses. Due to the inferior optical characteristics of these overlapping regions, a light passing through the overlapping regions tends to be weak. In other words, under a same exposure condition, the formation of the overlapping regions results in an insufficient exposure dosage for the photoresist material layer corresponding to the overlapping regions. Consequently, photoresist patterns having large line widths and small spacings are formed. Therefore, although the strip patterns formed by using the photoresist patterns as the mask have a same pitch (e.g., a sum of the line width and spacing is the same), the strip patterns have different line width/spacing ratios, thereby causing an issue of bright and dark lines for the display of the PSA-LCD panel, which is a phenomenon known as “lens mura”.